Fuel filter cartridge and keyed end cap

ABSTRACT

A filter cartridge has a keyed end cap which is configured and shaped for unlocking an associated valve mechanism that comprises a latch device and a valve. In this manner, when the fuel filter cartridge is placed into a fuel filter housing having such a latch and valve mechanism, the fuel filter cartridge is operable therein to filter fluid and pass the fluid into a standpipe contained within the fuel filter housing. The fuel filter cartridge of this type generally includes pleated filter paper which is disposed between two opposed end caps. The keys may be provided along the bottom end cap.

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS

This patent application is a continuation-in-part application ofco-pending U.S. patent application Ser. No. 10/940,002, filed Sep. 13,2004, the disclosure and teachings of which are incorporated herein intheir entireties, by reference thereto.

FIELD OF THE INVENTION

The present invention generally relates to filters and their componentsand more particularly relates to filter cartridges and end capstherefore which are configured to engage flow control valves in filterhousings.

BACKGROUND OF THE INVENTION

The present invention relates to keyed fuel filter cartridges for a fuelfilter housing which has a keyed latch shut-off valve as shown forexample in U.S. Pat. Nos. 6,495,042 and 6,550,000, the entiredisclosures of which are hereby incorporated by reference. As disclosedgenerally in these patents, stepped keys are provided in a recess formedin the bottom end cap of a fuel filter cartridge. Each of the steppedkeys includes a valve actuation portion and a latch actuation portion,whereby the keys are used to unlock a latched device and move a valveelement and uncover a fuel flow port in a standpipe of a valve housing.It is known that these fuel filter cartridges are periodically replacedfrom time to time, but the fuel filter housing is permanent andtypically reused. In these applications the fuel filter cartridge ispulled from the fuel filter housing which returns the valve to theclosed position and the latch mechanism to the lock position. As aresult, when a new filter cartridge is installed there is a need to beable to again unlatch the latch device and then move the valve elementto uncover the opening in the standpipe. The present invention relatesto a fuel filter cartridge and end cap which may be used and applied tosuch fuel filter housings as disclosed in the '042 and '000 patentsreferenced above, or that may have other application.

BRIEF SUMMARY OF THE INVENTION

One aspect of the present invention is directed toward a fuel filter.The fuel filter includes a tube of filter media surrounding alongitudinal axis. A first end cap is placed on the first end of thetube of filtering media. The first end cap defines a first annulartrough that is filled with potting compound to connect and seal thefirst end cap to the tube of filtering media. The first end cap definesa first central opening surrounding the longitudinal axis. A second endcap is located on the second end of the tube of filtering media. Thesecond end cap includes an outer annular skirt portion, an inner annularskirt port and a disc portion therebetween. The second end cap defines asecond annular trough along the disc portion between the skirt portionswhich has potting compound therein which connects and seals the firstend cap to the tube of filtering media. The second end cap defines asecond central opening which surrounds the longitudinal axis. Unlike theprior art, a plurality of keys are located on the disc portion andproject axially from the disc portion in a direction away from thefiltering media. The keys are arranged in an annular array surroundingthe axis.

Another aspect of the present invention is directed toward an end capfor such a fuel filter cartridge. The end cap includes an outer annularskirt portion, an inner annular skirt portion and a disc portiontherebetween. An annular trough is formed along the disc portion betweenthe skirt portions on an underside of the end cap. A central opening isformed into the disc portion and surrounds the longitudinal axis. Aplurality of keys are located on the disc portion and project axiallyfrom the disc portion. These keys are arranged in an annular array whichsurrounds the axis.

According to a different aspect and different embodiment of the presentinvention, a fuel filter comprises a tube of filtering media and firstand second end caps placed upon opposing ends of the tube of filteringmedia. One of the end caps includes a cylindrical recess structure.Located in the recess structure is a first plurality of keys whichproject in the recess in an annular array and a second plurality of keysprojecting in the recess in an annular array which are of a differentcharacteristic than the first plurality of keys.

Other aspects, objectives and advantages of the invention will becomemore apparent from the following detailed description when taken inconjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings incorporated in and forming a part of thespecification illustrate several aspects of the present invention and,together with the description, serve to explain the principles of theinvention. In the drawings:

FIG. 1 is a cross-section of a fuel filter cartridge in accordance witha first embodiment of the present invention.

FIG. 2 is a cross-section of the bottom end cap portion of the fuelfilter cartridge shown in FIG. 1 as installed on a standpipe in a fuelfilter housing and engaging a latch and valve mechanism therein.

FIG. 3 is an isometric view of the bottom end cap of the fuel filtercartridge of FIG. 1.

FIG. 4 is a view similar to FIG. 3, but with the end cap cut in half.

FIG. 5 is a bottom end view of the bottom end cap for the fuel filter ofthe first embodiment shown in FIG. 1.

FIG. 6 is a cross-section of FIG. 5 taken about line 6-6.

FIGS. 7 and 8 are enlarged views of different portions of FIG. 6.

FIG. 9 is a view of a bottom end cap of a second embodiment of thepresent invention for a fuel filter cartridge.

FIG. 10 is a view of the end cap of the second embodiment as mounted ona filter cartridge.

FIG. 11 is a plan bottom view of the second embodiment of the end capshown in FIG. 9.

FIG. 12 is a cross-section of FIG. 11 taken about line 12-12.

FIGS. 13 and 14 are enlarged views of different portions of FIG. 12.

FIG. 15 is an isometric view of a third embodiment of the end cap whichmay be used on a filter cartridge.

FIG. 16 is a view of the third embodiment of the end cap shown in FIG.15 as mounted on a fuel filter cartridge.

FIG. 17 is a bottom plan view of the end cap according to the thirdembodiment shown in FIG. 15.

FIG. 18 is a cross-section of the end cap shown in FIG. 17.

FIG. 19 is an enlarged view of a portion of FIG. 18.

FIGS. 20 and 21 are isometric views of a bottom end cap for use in afuel filter cartridge according to a fourth embodiment in which FIGS. 20and 21 show different perspectives of the bottom end cap.

FIG. 22 is a plan view of an inward side of the bottom end cap of thefourth embodiment shown in FIGS. 20 and 21.

FIG. 23 is a cross-section of the end cap shown in FIG. 22.

FIGS. 24 and 25 are enlarged portions of different segments of thecross-section shown in FIG. 23.

FIG. 26 is a view of the end cap of the fourth embodiment as mounted ona filter cartridge.

FIG. 27 is an isometric view of a fifth embodiment of a filtercartridge.

FIG. 28 is an exploded illustration of the end cap of the filtercartridge shown in FIG. 27.

FIG. 29 is a cross-section of the end cap shown in FIG. 28.

FIG. 30 is an isometric view of a sixth embodiment of a filter cartridgewhich may be used on a filter cartridge.

FIG. 31 is cross-section of the end cap of FIG. 30.

While the invention will be described in connection with certainpreferred embodiments, there is no intent to limit it to thoseembodiments. On the contrary, the intent is to cover all alternatives,modifications and equivalents as included within the spirit and scope ofthe invention as defined by the appended claims.

DETAILED DESCRIPTION OF THE INVENTION

Referring to the first embodiment of FIGS. 1-8, the invention isembodied in a fuel filter cartridge 10 as shown in FIG. 1 which isremovably installed into a fuel filter housing 12, the relevant portionsof which are shown in FIG. 2. This housing 12 depicts an exemplaryenvironment in which the fuel filter cartridge 10 will operate. As showntherein, the fuel filter housing includes a container 14 into which thefuel filter cartridge 10 is axially inserted along a longitudinal axis16 (longitudinal axis 16 also designates the central axis for the fuelfilter cartridge 10). Concentric and co-axial with the longitudinal axisis a fuel standpipe 18 which carries a spring loaded latch device 20 inthe form of a sleeve and a flow control valve 22 which opens and closesa fuel flow port 24 that extends radially through the standpipe 18. Asshown in FIG. 2, different halves of the longitudinal axis 16 depictdifferent engagement positions at different stages of axial insertion ofthe fuel filter cartridge 10 into the fuel filter housing 12. As showntherein, the fuel filter cartridge 10 will first engage the latch device20 and then subsequently engage the valve 22 to uncover the flow port toallow for fuel flow from the central region of the fuel filter cartridge10 into the standpipe 18. Further details of such a fuel filter housingand standpipe can be had to the referenced patents set forth in thebackground above.

With an exemplary operating environment for the present embodiment beingunderstood, attention will now be directed toward the fuel filtercartridge 10. The fuel filter cartridge 10 generally includes acylindrical tube of filtering media 30 that is concentric around thelongitudinal axis 16. The tube of filtering media 30 may comprise acylindrical ring of pleated filter paper, or may comprise other suitablefiltering media. A perforated metal or plastic central support tube 32may be provided concentrically inside the filtering media 30 to providefor radial support to the filtering media 30. The support tube 32provides support for the media 30 when fuel is flowing radially inwardthrough the filtering media 30.

At the top end of the filter cartridge 10 with the given orientationshown in FIG. 1, there is a top end cap 34. The top end cap 34 definesan annular trough 36 along the underside thereof. The annular trough 36that receives potting compound 38 (such as plastisol, adhesive or othersuitable bonding agent) which connects and seals the top end cap 34 tothe top end of the filtering media 30. The top end cap 34 defines acentral opening 40 which is sized to receive the standpipe 18therethrough. Along the inner lip of the central opening 40 the top endcap 34 carries an annular gasket 42 which engages and seals against thestandpipe 18 shown in FIG. 2 when installed into the fuel filter housing12. A collapsible handle 44 may also be mounted to the top end cap 34 toprovide a means for ready removal of the fuel filter cartridge at filterchange interval time. The handle 44 can be pulled to facilitate removalof the fuel filter cartridge

Turning to the bottom side of the filter cartridge 10, a bottom end cap50 is provided. The bottom end cap 50 may be comprised of two separatecomponent plastic parts including a generally plate-shaped member 52 anda generally ring-shaped member 54 which are assembled together as shown.One method for assembling the two members 52 and 54 together is asnap-lock connection in which snap tabs 56 projecting from one of themembers 54 is snapped onto corresponding structure on the other member52 to form the bottom end cap 50.

The bottom end cap 50 once assembled includes an outer annular skirt 58,an inner skirt 60 and a generally planar disc portion 62 therebetween.The combination of these structural portions provides an annular trough64 which is received onto the bottom end of the filtering media 30 andconnected and sealed thereto by potting compound 66. The inner peripheryof the disc portion 62 defines a central opening 68 which may berecessed into the filtering media 30 as indicted via the inner skirt 60.The inner skirt 60 extends axially inward and terminates in a radiallyinward extending bottom wall 70 to form a generally cylindrical recess72. The bottom wall 70 is generally planar in nature and extendsradially inward toward a further central opening 74 that is of a smallerdiameter than the outer central opening 68. The bottom wall 70 in thisembodiment is used as the valve actuation means as shown in FIG. 2.Surrounding the central opening 74 is a loop structure or lip 76 whichis configured to slidably engage the standpipe and provides for someflexibility to allow for easier axial installation and locationfeatures. The lip 76 which extends axially also flexes slightly inwardlyand outwardly radially relative to the standpipe.

Since the valve 22 cannot be actuated without first removing theprotective latch device 20 as shown in FIG. 2, the bottom end cap 50also provides means for engaging the latch device which is shown in theform of an annular array of keys 82. The keys 82 are not located in therecess 72 but are located on the disc portion 62 and project axiallyfrom the disc portion 62 in an outward direction, which is away from thefiltering media 30. The keys 82 are arranged in an annular array whichsurrounds the central longitudinal axis 16.

As shown in the figures, the keys 82 project radially inward past theouter central opening 68 in a cantilever manner such that gaps 84 areformed between adjacent keys to provide suitable clearance for use withthe associated standpipe and valve/latch mechanism. The keys arearranged and spaced to provide means for releasing the latch device 20of the flow control valve 22 in the filter housing. The keys 82 areconfigured and spaced relative to the valve actuating bottom wall 70 soas to compliment the configuration of the latch device 20 and valve 22of the fuel filter housing. To achieve this, the keys 82 only extendpartially radially inward and short of the diameter of the inner centralopening 74. With this configuration, there is no longer a requirementthat the outer face of the keys be stepped. Instead as shown the keys 82may have an outer surface 88 which is relatively straight in the radialdirection. The keys 82 may also be elevated slightly by a raised annularplateau portion 90 which is formed into the disc portion 62 of theplate-shaped member 52. This raised plateau portion 90 also providesalong the inward side a recess area to receive a radial projection ofthe ring-shaped member 54 and thereby provide a flat underside surfacefor the annular trough 64 to better ensure connection and sealingbetween the bottom end cap 50 and the filtering media 30 via the pottingcompound 66.

Turning to the second embodiment of the present invention shown in FIGS.9-14, a disposable fuel filter cartridge 110 is illustrated which willbe understood to be similar in most material respects to FIG. 1, withthe primary exception being the configuration and keying mechanism ofthe bottom end cap 112. Accordingly, focus as applied to this embodimentwill be directed to the principle distinctions. In this embodiment, thebottom end cap 112 still includes keys 114 which project from the discportion 116 of the bottom end cap 112. Similar to the first embodiment,the keys 114 avoid and are clear of the recess structure 118 formed intothe bottom end cap 112. However, as opposed to the first embodimentwhere the bottom wall of the recess provides the valve actuation means,in this embodiment the keys 114 themselves provide for both the latchactuation means and the valve actuation means. In particular, the keys114 are stepped to include a first latch actuation surface 120 and asecond valve actuation surface 122. These surfaces 120, 122 are bothaxially and radially spaced with a configuration and spacing that iscomplimentary to that of the latch device and valve of a correspondingfuel filter housing.

Turning to a third embodiment of the present invention, with referenceto FIGS. 15-19, it will be understood that the fuel filter cartridge 210of the third embodiment is much like the earlier two embodiments with aprinciple distinction being the configuration and shape of the bottomend cap 212. In this embodiment, the bottom end cap 212 may be formed ofa single unitary member rather than two component part members which areassembled together. Further, this embodiment eliminates the recessstructure of prior embodiments and instead the keys 214 are formed onthe outer face or disc portion 216 of the bottom end cap projectingaxially outward therefrom (in a direction away from the filteringmedia). Similar to the second embodiment, these keys 214 also include astepped surface to include a latch actuation surface 120 and a valveactuation surface 122 which are both radially and axially spacedrelative to each other. A potential advantage of an embodiment like thisis that the inner diameter of the filtering media may be moved inwardlyif desired (e.g. the inner diameter of the filtering media may besmaller).

A fourth embodiment of a fuel filter cartridge 310 is shown in FIGS.20-26, which will be understood to be in many respects similar to theearlier embodiments of fuel filter cartridges again with the principleexception being the configuration and operation of the bottom end cap312. This embodiment has significant distinctions as opposed to theearlier embodiments in that at least two different type of keys 314, 316are provided. Also opposed to earlier embodiments, the keys 314 and 316are not disposed on the end face of the bottom end cap 312, but insteadlocated and supported in the cylindrical recess 318 of the bottom endcap 312. However, rather than providing for a complex stepped surface oneach of the keys, this embodiment uses two different types of keys 314,316 of a different characteristic. In particular, the first set of keys314 are axially longer and radially skinnier that the second set of keys316. In this manner, one set of the keys 314 are used to engage andunlock the latch device while the other set of keys 316 are used toactuate the valve and thereby open the flow port. The two sets of keys314 and 316 are arranged in a common circular array. Also, the keys 314,316 of this embodiment are not cantilevered with the support only alongone side, but instead supported along two different sides of each of thekeys including a first side connected to the inner annular skirt and asecond side connected to the bottom wall.

A fifth embodiment of a filter cartridge 410 is shown in FIG. 27, whichwill be understood to be in many respects similar to the earlierembodiments of fuel filter cartridges, with the principle exceptionbeing the configuration and operation of the bottom end cap 412.Additional reference may be had to FIGS. 28 and 29. This end capembodiment is a multi-part embodiment that includes two portionsincluding a cap portion 411 and a key portion 413. The key portion 413is preferably snap-fit engaged to an end face of cap portion 411. Thecap portion 411 includes cavities 421 formed in ring or disc portion 415that receive prongs 420 of the key portion 413 to facilitate thesnap-fit engagement. The prongs 420 extend from a generally annular discportion 417.

The key portion 413 includes at least two different types of keys 414,416 interconnected to one another by the disc portion 417. Due to thearrangement of the key portion 413 relative to the cap portion 411, thekeys 414, 416 are disposed on the end face of end cap 414. However,rather than providing for a complex stepped surface on each of the keys,this embodiment uses two different types of keys 414, 416 of a differentcharacteristic. In particular, the first set of keys 414 are axiallylonger that the second set of keys 416. In this manner, one set of thekeys 414 are used to engage and unlock the latch device while the otherset of keys 416 are used to actuate the valve and thereby open the flowport.

Further, the first set of keys 414 have a different shape characteristicthan the second set of keys 416. The first set of keys 414 are“Y-shaped” including a base portion extending substantially radiallyoutward and two leg portions extending at non-zero angle relative to thebase portion. As illustrated, the two leg portions extend at acuteangles relative to the base portion and the base portion bisects anangle formed by the two leg portions, but the base portion does notextend between the two leg portions in this embodiment. Preferably, thekeys of a given set are arranged in a common angular array. The secondset of keys 416 are generally planar. The base portion includes a distalend that is radially inward of the leg portions and the connectionbetween the base portion and the leg portions.

The cap portion 411 includes an axially extending central openingsurrounded by a loop structure or lip 423 which is configured toslidably engage the standpipe and provides for some flexibility to allowfor easier axial installation and location features. The lip 423, whichextends axially also flexes slightly inwardly and outwardly radiallyrelative to the standpipe.

It should be noted, that although this end cap embodiment is illustratedas being a multi-part end cap, it is contemplated that the two end capportions 411, 413 could be formed in a unitary one piece construction inother embodiments.

A sixth embodiment of an end cap 512 for use in a filter cartridgeaccording to the present invention is provided in FIGS. 30 and 31. Thisembodiment is similar to the embodiment illustrated in FIGS. 27-29 inmany respects except that the first set of keys 514 is configureddifferently than the embodiment in FIGS. 27-29. In this embodiment, thefirst set of keys 514 is generally “crowfoot-shaped”. Alternatively, thekeys 514 could be viewed as being “Y-shaped” with the base 519 extendingradially outward such that a portion is interposed between the two legportions 521 forming the Y-shape. As illustrated, the base 519 bisectsthe angle formed by the two leg portions 521. Again, the first set ofkeys 514 is axially longer than the second set of keys 516.

The base portion 519 includes a first distal end that is radially inwardof the leg portions 521 and the connection between the base portion 519and the leg portions 521 as well as a second distal end that isinterposed between the two leg portions 521. Generally, the portion ofthe base portion 519 between the first distal end and the intersectionof the leg portions 521 and the base portion 519 is used to engage thelatch of the valve. However, this is not required in practicingembodiments of the present invention.

The Y-shape or crowfoot shape of the previous two embodimentsfacilitates manufacture of the filter element. The increased materialprovided by and angled orientation of the legs (i.e. legs 519) preventdeformation of the keys 414, 514 when filter media is secured to the endcaps 414, 416. Further, the Y-shape or crowfoot shape increases orwidens the foot print of the keys to increase stability of the end capwhen riding on a conveyor during manufacturing.

In this embodiment, the keys 514, 516 are directly formed into the discportion 515 of the end cap 512. As such, the end cap 512 is a one-pieceunitary construction. Again, the end cap 512 includes an axiallyextending central opening formed by a sealing lip 523.

All references, including publications, patent applications, and patentscited herein are hereby incorporated by reference to the same extent asif each reference were individually and specifically indicated to beincorporated by reference and were set forth in its entirety herein.

The use of the terms “a” and “an” and “the” and similar referents in thecontext of describing the invention (especially in the context of thefollowing claims) is to be construed to cover both the singular and theplural, unless otherwise indicated herein or clearly contradicted bycontext. The terms “comprising,” “having,” “including,” and “containing”are to be construed as open-ended terms (i.e., meaning “including, butnot limited to,”) unless otherwise noted. Recitation of ranges of valuesherein are merely intended to serve as a shorthand method of referringindividually to each separate value falling within the range, unlessotherwise indicated herein, and each separate value is incorporated intothe specification as if it were individually recited herein. All methodsdescribed herein can be performed in any suitable order unless otherwiseindicated herein or otherwise clearly contradicted by context. The useof any and all examples, or exemplary language (e.g., “such as”)provided herein, is intended merely to better illuminate the inventionand does not pose a limitation on the scope of the invention unlessotherwise claimed. No language in the specification should be construedas indicating any non-claimed element as essential to the practice ofthe invention.

Preferred embodiments of this invention are described herein, includingthe best mode known to the inventors for carrying out the invention.Variations of those preferred embodiments may become apparent to thoseof ordinary skill in the art upon reading the foregoing description. Theinventors expect skilled artisans to employ such variations asappropriate, and the inventors intend for the invention to be practicedotherwise than as specifically described herein. Accordingly, thisinvention includes all modifications and equivalents of the subjectmatter recited in the claims appended hereto as permitted by applicablelaw. Moreover, any combination of the above-described elements in allpossible variations thereof is encompassed by the invention unlessotherwise indicated herein or otherwise clearly contradicted by context.

1. A filter assembly, comprising: a filter housing defining a housingcavity; a valve assembly within the housing cavity, the valve assemblyincluding: a central standpipe defining a central flow passage includinga flow port; a flow control valve including a valve portion surroundingthe standpipe and axially movable therealong between a closed positionwherein the valve portion covers the flow port preventing fluid flowtherethrough and an open position wherein the valve portion ispositioned to uncover the flow port and permit fluid flow therethrough;a filter element within the housing cavity of the filter housing, thefilter element engaging the flow control valve and maintaining the flowcontrol valve in the open position, the filter element including: a tubeof filter media extending between opposed first and second ends andsurrounding a longitudinal axis; a first end cap sealingly connected tothe first end of the tube of filter media; a second end cap having aninner and outer face, the inner face sealingly connected to the secondend of the tube of filter media, the first end cap, second end cap andfilter media defining a central cavity therebetween, the second end capincluding a disc portion including a central opening surrounding thelongitudinal axis and opening to the central cavity; a first pluralityof keys located on the outer face and axially projecting from the outerface in a direction extending away from the filter media, the first keysbeing arranged in a first annular array surrounding the longitudinalaxis, and the first keys being axially spaced from the filter media, thekeys acting upon the valve assembly and the filter element maintainingthe flow control valve in the open position, the first keys extendingradially outward beyond an inner diameter of the tube of filter media.2. The filter assembly of claim 1, wherein gaps are formed betweenadjacent first keys completely angularly separating the adjacent firstkeys.
 3. The filter assembly of claim 1, wherein the valve assemblyfurther comprises a latch device movable axially along the centralstandpipe, the latch device having a locked position maintaining theflow control valve in the closed position and an unlocked positionpermitting the flow control valve to transition to the open position,the filter element engaging and maintaining the latch device in theunlocked position.
 4. The filter assembly of claim 3, wherein each firstkey includes a first abutment face and a second abutment face, the firstface spaced axially from the second face in a direction extending awayfrom the first end cap and spaced radially outward relative to thesecond face, the first face axially abutting the latch device and thesecond face axially abutting the flow control valve.
 5. The filterassembly of claim 4, wherein the first and second faces, the latchdevice, the abutment between the latch device and first keys and theabutment between the filter element and the flow control valve areaxially spaced from the filter media.
 6. The filter assembly of claim 3,wherein the second end cap axially abuts the flow control valve in theopen position and the first keys axially abut the latch device.
 7. Thefilter assembly of claim 5, wherein the first and second faces have afirst axial spacing being greater than a second axial spacing betweenthe corresponding portions of the latch device and flow control valve towhich the first and second faces abut, respectively, such that the firstface abuts the latch device prior to the second face abutting the flowcontrol valve.
 8. The filter assembly of claim 4, wherein the first keysand the second end cap are formed as a single unitary member and thefilter element is removably positioned within the filter housing.
 9. Thefilter assembly of claim 3, further comprising a plurality of secondkeys located on the outer face and projecting axially from the outerface in a direction extending away from the filter media, the secondkeys being arranged in a second annular array surrounding thelongitudinal axis, the first keys being independent of the second keys,the first keys engaging the latch device and the second keys engagingthe flow control valve, the second keys being of a differentcharacteristic than the first keys.
 10. The filter assembly of claim 9,wherein the first keys have a longer axial length than the second keys.11. The filter assembly of claim 9, wherein the first keys are angularlyspaced from second keys and the first keys have a wider radial widththan the second keys.
 12. The filter assembly of claim 9, wherein thefirst keys have a radially inner most edge that is radially closer tothe longitudinal axis than a radially inner most edge of the secondkeys.
 13. The filter assembly of claim 1, wherein the first keys actupon the flow control valve and maintain the flow control valve in theopen position.
 14. The filter assembly of claim 9, wherein the firstkeys are generally Y-shaped and the second keys are generally planar.